The invention concerns the technical sector of automatic machines for packing articles.
In general, these machines can be divided into “continuous drive” machines and “step drive” machines, on the basis of the type of motion imposed on the respective transporter lines
Sometimes continuous drive and step drive machines coexist in a production line; machines also exist which have transporter lines with continuous advancement and others with alternated step advancement.
Naturally, in the abovementioned cases, it becomes necessary to provide interfacing organs for reconciling the different modes of functioning and enabling transfer of the transported articles from a machine located upstream to a machine located downstream or from one line to another.
In these cases, intermediate conveyors of a particular type, known as “synchro-dynamic” transporters can be provided between the machines, or between contiguous sections of the machines, which transporters exhibit non-homogeneous drives. The particularity of these conveyors is that they provide different types of motion at inlet and outlet thereof.
“Synchro-dynamic” transporters have two advancement groups which extend along the same trajectory and are activated independently of each other; at least one series or gripping organs or crates, appropriately distanced from the other series, is associated to each advancement group; in this way a first series of organs or crates, situated upstream, can be driven continuously, while the remaining series, arranged downstream, is step driven, or vice versa.
In “synchro-dynamic” conveyors no intermediate stations between upstream and downstream are provided, therefore their function consists solely of “linking” two machines or transporter lines having different type of drive.
The present applicant has developed an automatic machine for filling and subsequently capping rigid tubular containers arranged vertically; a predetermined number of articles is inserted one at a time into each of the containers, and at the end of the filling operation, the articles are piled one on top of the other (please refer in this connection to Applicant's request no. BO2006A 000899).
This machine loads the containers into a conveyor one by one at an inlet station upstream, then transfers them first towards a filling station and, subsequently from there, through any intermediate stations present, then towards a capping station and further towards an outlet station downstream.
The abovementioned filling operation must necessarily be performed with the container at rest for a duration depending on the machine-time for a single insertion multiplied by the number of the insertions required to fill the container.
The other operations performed at the stations upstream and downstream of the filling station are obviously performed to coincide with the motion pause stage at the filling operation, even if they require shorter times than the filling operation.
In a first known technique, a traditional single-step conveyor is used to transport the containers and the pause period required between each advancement step must be calibrated on the basis of the time required for carrying out the longest of the operations, that is, the filling stage; the resulting machine is therefore extremely slow and provides unsatisfactory productivity.
A possible partial remedy for this drawback consists in providing multiple operating organs at each station, which are therefore capable of acting at the same time on two or more containers, with a conveyor activated in its turn with a multiple step which corresponds to the number of containers to be dealt with at each stage; in this way, a proportional increase of productivity is obtained with the same pause time.
This solution significantly complicates the construction of the machine's operating organs, with complications increasing proportionally to the number of containers to be treated simultaneously, and leads to a series of negative consequences, both in terms of costs and operational reliability.
Compared with the first technical solution, a nominally significant increase in productivity is obtained, since productivity doubles or trebles, yet in absolute terms this is still modest when compared with market requirements.
For the machine described above, and other machines with similar operational requirements, the need is felt for a conveyor which functions flexibly and is to some degree comparable with how a “synchrodynamic” conveyor interfaces between two transporter lines having different forms of activation.
Thus an aim of this invention is to provide a multiple conveyor for conveying containers through operating stations, which conveyor is to be associated to an automatic machine and designed in such a way as to adapt the advancement cycle of the containers to the optimal conditions for each operating station of the machine, in order to obtain both high productivity levels and the greatest-possible simplicity of construction for the operating organs situated in each of the stations.
A further aim of the invention is to provide a conveyor which, thanks to its characteristics, favors the achievement of high operational reliability of the machine to which it is associated.
A still further aim of the invention consists in providing a conveyor conformed in such a way that it allows rational machine lay-out configurations, in accordance with the ergonomics, size limitation, and location requirements of the various operating organs.
A further aim of the invention is to provide a method for conveying containers through operating stations which satisfies the technical-functional requirements of the various stations, while at the same time optimising each station's performance and positively affecting productivity relative to packing containers with relative products.
The above aims are obtained according to the contents of the appended claims.